brake float level sensor - standex electronics · complete brake float level sensor figure 2. brake...

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Automotive - Fluid LevelBrake Float Level Sensor

PARTNER | SOLVE | DELIVER


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© Standex-Meder Electronics. All Rights Reserved.

Introduction

When applying one’s foot to the brake pedal, it is taken for granted that the braking mechanism will begin to slow or stop the vehicle. A hermet-ically sealed reed switch plays a key reliability role by monitoring that the brake fluid level is maintained at its proper level. Low brake fluid level could mean the loss of the vehicle braking system.

Features

• All inclusive brake fluid sensor complete with switching element (Reed Switch), Float, and magnet

• Hermetically sealed• Dynamically tested contacts• Reliable switching• Accurate control of the open and closure

points• Wide hysteresis preventing on/off cycling• Ability to operate at very hot and cold tem-

peratures in an under the hood environment• Low cost • Housing vapor sealed• Different headers available for different vehi-

cles• Millions of reliable switching operations• Accurate control of the open and closure

points

Applications

• Sensing the fluid level in brake fluid reser-voirs

• Sensing fluid level in gasoline, oil and other liquid reservoirs

• Coolant overflow fluid system sensing

Figure 1. Complete Brake Float Level Sensor

Figure 2. Brake Fluid above low level- Reed Switch not activated

Figure 3. Brake Fluid Low Position- Reed Switch closed activating lamp indicator light


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MEDER’s Reliable Reed Approach To Brake Fluid Level Sensing Systems

Designing a sensing system for under the hood of a vehicle presents difficult requirements. The sensor must operate at extreme temperatures that are as low as -40°C and as high as 125°C. This dirty environment is typically visited by oil, gasoline, brake fluid, salt water and a host of solid particulates. Standex-Meder’s approach has been to use only the most reliable technolo-gy to insure quality operation and long reliability in the field for the life of the vehicle.

Since this sensor requires some electrical cir-cuitry, using a printed circuit board with plated thru solder holes guarantees reliable connec-tions using an automated wave soldering sys-tem. Others have chosen welding technology which can guarantee a good connection, but

can also damage the delicate hermetic seal of the reed switch with its high temperature point contact and its tough mechanical approach. This poses an even bigger problem in the field if a slight crack of the reed switch seal occurs during assembly, as it could take up to a year or more for enough gas and/or moisture to leak into the capsule to oxidize the contacts. Then if the brake fluid drops below acceptable limits the contacts would fail to close; therefore, not alerting the driver that a critical situation has developed. Figures 2 and 3 show the proper operating sequence.

Also, part of our design criteria is to build suffi-cient hysteresis into the operation of the sensor. This insures once the sensor activates, it will not go on and off with every sway of the vehicle or bump in the road.

Another critical element is the acknowledge-ment that during assembly problems can occur. Standex-Meder tests all sensors 100% for all operating conditions, but in addition tests for dynamic contact resistance (DCR). Essentially this test is a guard against the many faults that can occur during assembly. If the reed contacts have any internal contaminations; or the reed capsule has been stressed or a slight crack has occurred, this DCR will detect these conditions and reject the sensor. This testing is all car-ried out in an automated testing system that is independent of any operator, and rejected parts are automatically placed in a lock box. Stan-dex-Meder’s design for manufacturing approach provides a long reliable life in the field.

Specifications (@ 20°C) LSS SeriesMin Max Units

Operate SpecificationsMust close distance Ref Ref mmMust open distance Ref Ref mmHysteresisLoad characteristicsSwitching voltage 200 VSwitching current 0.5 AmpsCarry current 1.0 AmpsContact rating 10 WattsStatic contact resistance 150 mΩDynamic contact resistance 200 mΩBreakdown voltage 2000 VOperate time 0.4 msecRelease time 0.05 msecOperate temp -40 125 °CStorage temp -65 150 °C


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The header and sleeve shown in the dimension-al diagram have several other potential options allowing different connectors to be used, as well as the ability to fit into several other types of brake fluid reservoirs.

Consider some of the below liquid level sensors for similar brake float sensor applications.

Find out more about our ability to propel your business with our products by visiting www.standexmeder.com or by giving us a [email protected] today! One of our brilliant engineers or solution selling sales leaders will listen to you immediately.

Single Point Liquid Level SeriesDimenstions

mm inches IllustrationSeries

KSS-BV10113

W 17 0.669

H 44 1.732

L 58 2.283

LS01 W 19 0.748

H 24 0.945

L 42 1.654

LS02 W 19 0.748

H 24 0.945

L 75 2.953

LS03 W 25 0.948

H 25 0.948

L 80 3.150

**Consult the factory for more options not listed above.

About Standex-Meder Electronics

Standex-Meder Electronics is a worldwide market lead-er in the design, development and manufacture of stan-dard and custom electro-magnetic components, includ-ing magnetics products and reed switch-based solutions.

Our magnetic offerings include planar, Rogowski, current, and low- and high-frequency transformers and inductors. Our reed switch-based solutions include Meder, Standex and OKI brand reed switches, as well as a complete portfolio of reed relays, and a comprehensive array of fluid level, proximity, mo-tion, water flow, HVAC condensate, hydraulic pressure dif-ferential, capacitive, conductive and inductive sensors.

We offer engineered product solutions for a broad spec-trum of product applications in the automotive, med-ical, test and measurement, military and aerospace, as well as appliance and general industrial markets.

Standex-Meder Electronics has a commitment to absolute customer satisfaction and customer-driven innovation, with a global organization that offers sales support, engi-neering capabilities, and technical resources worldwide.

Headquartered in Cincinnati, Ohio, USA, Standex-Med-er Electronics has eight manufacturing facilities in six countries, located in the United States, Germany, China, Mexico, the United Kingdom, and Canada.

For more information on Standex-Meder Electronics, please visit us on the web at www.standexmeder.com. Contact Information:

Standex-Meder Electronics World Headquarters

4538 Camberwell RoadCincinnati, OH 45209 USA

Standex Americas (OH)+1.866.STANDEX (+1.866.782.6339)

[email protected]

Meder Americas (MA)+1.800.870.5385

[email protected]

Standex-Meder Asia (Shanghai)[email protected]

Standex-Meder Europe (Germany)+49.7731.8399.0

[email protected]

brake float level sensor - standex electronics · complete brake float level sensor figure 2. brake...

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